Storm Drainage Master Plan Draft: Comments for Final Version
Submitted by Ken Kormanak
1. Add Addresses – The report references lot addresses for projects and in the historical references, but none of
the figures show them. This makes it difficult to identify in the referenced figures the addresses where the work
will be performed. Recommend adding address numbers to the GIS layer and showing them in the final report,
especially if the community will be reading the document and trying to find the location of each project.
2. History of Flooding Within the District – page 1-5 – If possible, it would be nice to know under what storm
conditions flooding occurs within each area. That is, does it take only an annual normal rainfall to flood some
areas, but a 10-year event to flood others? Noting each area number would help to understand the priority
given to each project, not just the water-carrying capacity of the pipes.
3. Master Plan Draft - page 3-19 - Historical Problem Areas - The historical background for the Ramona Road/Vista
Verde intersection references a historical flood event that occurred during a large storm during the 1997-1998
rainfall season (66.17” that period per Gene Hunner’s local records) and a series of landslides that occurred on
the same property for several years. The flood was primarily a man-made event caused by a developer grading
off the topsoil for a building site at 195 Vista Verde. Three homes above the site had diverted their rain runoff
to flow down to a corner of the exposed construction site’s soil. This runoff caused the ground to become
saturated and slide down Ramona Road and pour across the downslope properties during a particularly severe
rainstorm that year.
There was an additional problem in that area concerning an annual landslide at the Vista Verde/Ramona Road
intersection of the 195 Vista Verde Way property. About a ½ dump truck’s worth soil was removed each year
after the winter storms from this location. A retaining wall and French Drain that has two 6” and 4” drainpipes
solved this problem. Now these drain pipes enter the culvert at the road intersection to drain the hillside’s
water through the 15” culvert’s pipe.
The developer’s slide during the 1998 storm and the annual landslide issues have been corrected so that there
have been no further incidents in the past 24 years from that man-made condition. The report should add this
additional information, for the sake of completeness and accuracy.
There is evidence that the entire hill is sliding as evidenced by buckling of the asphalt between the homes at 400
and 441 Ramona Road. It was pointed out at the November 7, 2013 LTCWD meeting that the concrete-asbestos
water pipe broke and was repaired about 3 times due to apparent pressure compressing the pipe and breaking
it due to sliding. I cannot say on what dates these pipe breaks occurred. There have not been any more breaks
recently or evidence of sliding, but the buckled road is still in need of re-paving.
4. Appendix H1 - Site Photos - The culvert photos 80 and 81 should be updated to show the extensive recent
changes that the San Mateo County Department of Public Works (SMCDPW) performed to clear the Spanish
Creek drainage area, excavate the culvert, and provide a method of holding back debris from entering the
culvert inflow opening. This new work should be reflected in the wording of the report.
11/08/2013 - Ken Kormanak - 450 Ramona Road kenkorm@hotmail.com 650-464-1038
Storm Drainage Master Plan Draft: Comments for Final Version
Note: I can provide higher-quality pictures, if you need them.
County-installed boulders connected by rebar to catch
large debris from entering the culvert across from
281 Ramona Road.
Cleaned out catch basin near 281 Ramona Road, viewed with
Ramona Road in the background.
11/08/2013 - Ken Kormanak - 450 Ramona Road kenkorm@hotmail.com 650-464-1038
Storm Drainage Master Plan Draft: Comments for Final Version
5. Appendix H1 - Site Photos - New photos should be made to replace photos 81, 82, 83, and 84 along with an
update to the report. Or, these could be displayed as before-and-after photos. This update should cover the
recent road repair, and drainage work done to the Ramona Road slide fix at the Spanish Creek area to reflect the
improvements made by the SMDPW to correct and improve the road and drainage at that area.
Ramona Road slide repair with 281 Ramona Road in the background.
Repaired Ramona Road slide area with hydro-seeded slope
and drain pipe from French drain.
11/08/2013 - Ken Kormanak - 450 Ramona Road kenkorm@hotmail.com 650-464-1038
Storm Drainage Master Plan Draft: Comments for Final Version
Drain pipe from base of retaining wall to carry water towards Los Trancos Creek.
6. Maintenance - Please emphasize the importance of interim maintenance measures that can be done by the
homeowners, County, and LTCWD to minimize the potential for flooding by clearing out private culverts, and
checking the condition of pipes that cross private property.
7. Glossary – It would be good for residents, who will be reading this document, to have a glossary of terms that
they might not be familiar with in the document (MH, CB, CMP, Rolled Culvert, etc.).
11/08/2013 - Ken Kormanak - 450 Ramona Road kenkorm@hotmail.com 650-464-1038